1. Field of the Invention
The present invention concerns a local coil arrangement for magnetic resonance applications, of the type wherein the local coil arrangement has a base body and at least one local coil is arranged in the base body, and wherein an excitation signal to excite an examination subject to emit a magnetic resonance signal is emitted by the local coil and/or a magnetic resonance signal emitted by the examination subject is received, and wherein at least one volume region is present in the base body, in which volume region is located an amount of a substance that can be excited by the coil or another coil to emit a magnetic resonance signal.
2. Description of the Prior Art
Local coil arrangements of the above type are known.
In magnetic resonance examinations, local coil arrangements are normally used that can be freely positioned on the top of the patient (“anterior” if the patient is located in a dorsal position) within defined limits. However, for magnetic resonance examinations it has proven to be advantageous to know not only the approximate but rather the precise position of the local coil arrangement.
In the prior art, before the actual measurement an overview magnetic resonance image is produced from which the position of the local coil arrangement can be calculated automatically with certain precision limits if, for example, “characteristic antenna profiles” of the local coil are known. However, ambiguities (that can be caused by the use of multiple local coil arrangements or the use of one local coil arrangement with multiple local coils, for example) cause difficulties. Therefore, a method that is not based on the characteristic antenna profiles would be preferred.
To solve this problem, it is known to embed items known as “markers” into the base body. The “marker” is a substance that can be localized in a magnetic resonance image. The “marker” is therefore arranged in a volume region. It is composed of an amount of a substance that can be excited by the coil or a different coil to emit a magnetic resonance signal.
If the substance is the same substance that is also detected in the actual examination (for example hydrogen nuclei), the market itself can even be visible in the actual patient examination. This interferes as an aliasing artifact in the phase coding directions.
Alternatively, it is possible to use nuclei of other elements as markers, for example 31P or 19F. In this case, however, the entire radio-frequency system of the magnetic resonance system (transmission system, reception system and antenna system) must be able to transmit and to receive on the corresponding other frequency. Corresponding multiple applications that increase the price of the magnetic resonance system are required for this.